matters for the design of the CSR policy (e.g. should the fraction of the firm’s profits that is donated
to the social cause be linked to workers’ productivity or not).
While these two approaches have proved to be useful in deriving theoretical insights as to
the implications of workers’ pro-social preferences, no attempt to quantify and discriminate the
importance of the two using non-experimental data has been made, in part because appropriate
field data that would allow for sound econometric analysis are difficult to come by. In this paper
we report findings from a controlled experiment which is a first, to our knowledge, attempt to
disentangle and quantify the two sources of intrinsic motivation. An important aspect of our
design is that we observe subjects providing real effort in a natural work environment, thus heeding
Levitt and List (2007) who argue that pro-social behavior observed in the lab may not translate
into behavior in the field. A related point is made by Della Vigna (2009) in a recent review of the
literature on economics and psychology, who points out that “the research on social preferences
displays more imbalance between laboratory and field” compared to research on other topics and
calls for “more papers linking the findings in the laboratory [...] to the evidence in the field” (pg
341). Similar type of labor market field experiments using student workers have been recently used
to evaluate how various behavioral considerations, such as, reciprocity and peer effects operate in
labor markets (Falk and Ichino, 2006; Gneezy and List, 2006; Hennig-Schmidt et al., 2008).
We hired university students through email announcements to perform a short-term computer
data entry job on two separate occasions (one hour each). Using a short term job has the advantage
of removing career concern aspects or repeated game strategies that may represent a confounding
factor for the interpretation of the results (Bandiera et al., 2005). On the first occasion we paid
all students £10 plus a performance bonus based on their performance. On the second occasion,
we randomized students into three different groups. For the first group the second occasion was
identical to the first one. This baseline condition acts as our control, as it accounts for any change
in productivity due to experience, learning and so on. For the two other groups, we implemented
two treatments aimed at eliciting, respectively, action-oriented effort and effort that is induced by
both types of altruistic preferences. More specifically, in treatment A, we adapted the methodology
developed by Crumpler and Grossman (2008), which aimed at isolating and measuring warm-glow
giving in a laboratory setting, using a dictator game where the recipient was a charity. In that
paper, subjects were given a monetary endowment and were asked how much of that they would
want to allocate to a charity when the contribution of the subject crowded out the contribution of
the experimenter such that the charity always received a fixed amount. They found that subjects
donated on average 20% of their endowment, which provides evidence of the strength of the warm